1. Field of the Invention
The present invention relates to an imaging device having an electronic level function.
2. Description of the Prior Art
For example, Japanese Patent Application Publication No. 2009-94987 discloses an imaging device including an electronic level and an acceleration sensor to indicate the inclination of the device. In general the acceleration sensor is used to detect the aspect (length and breadth) of a captured image to display the captured image in the right aspect together with the electronic level. Further, Japanese Patent Application Publication No. 2009-225201 discloses an imaging device configured to detect an impact on the imaging device with an acceleration sensor and store a result of the detection as a log. Japanese Patent Application Publication No. 2006-292690 discloses an imaging device configured to detect an impact on the device by changing a measuring range and a sampling interval of an acceleration sensor after the occurrence of a free fall.
However, there is a problem in the imaging device in the JP2006-292690 document that it cannot deal with an impact on the device when it hits an object or a surface without a free fall. Another problem is that the acceleration sensor can be used for both the electronic level and the impact detection but required precision of the acceleration sensor is different in the electronic level and the impact detection. For the electronic level, the accelerator sensor is required to detect acceleration gravity so that sufficient measuring range thereof will be 1 G. For the impact detection, it is required to exert the measuring range of several G or more depending on a desired amount of impact to be detected. Also, a required sampling interval of the acceleration sensor is different in the electronic level and the impact detection. The sampling interval has to be set very short in the impact detection to be able to detect an instant impact. It is preferable to directly use the output values of the acceleration sensor.
For the purpose of improving the precision of the electronic level, a shorter sampling interval is preferable, however, it does not need to be as short as that in the impact detection. Further, the output values of the acceleration sensor need to be averaged to reduce a variation in the values.